Fast Inertial Microfluidic Actuation and Manipulation Using Surface Acoustic Waves

2010 ◽  
Author(s):  
Leslie Y. Yeo ◽  
James R. Friend
Keyword(s):  
Acoustic Waves ◽  
Substrate Surface ◽  
Surface Acoustic Waves ◽  
Nanoparticle Synthesis ◽  
Fluid Flows ◽  
The Body ◽  
Acoustic Energy ◽  
Liquid Jets ◽  
Micron Diameter ◽  
Drop Interface

Though uncommon in most microfluidic systems due to the dominance of viscous and capillary stresses, it is possible to drive microscale fluid flows with considerable inertia using surface acoustic waves (SAWs), which are nanometer order amplitude electro-elastic waves that can be generated on a piezoelectric substrate. Due to the confinement of the acoustic energy to a thin localized region along the substrate surface and its subsequent leakage into the body of liquid with which the substrate comes into contact, SAWs are an extremely efficient mechanism for driving fast microfluidics. We demonstrate that it is possible to generate a variety of efficient microfluidic flows using the SAW. For example, the SAWs can be exploited to pump liquids in microchannels or to translate free droplets typically one or two orders of magnitude faster than conventional electroosmotic or electrowetting technology. In addition, it is possible to drive strong microcentrifugation for micromixing and bioparticle concentration or separation. In the latter, rich and complex colloidal pattern formation dynamics have also been observed. At large input powers, the SAW is a powerful means for the generation of jets and atomized aerosol droplets through rapid destabilization of the parent drop interface. In the former, slender liquid jets that persist up to centimeters in length can be generated without requiring nozzles or orifices. In the latter, a monodispersed distribution of 1–10 micron diameter aerosol droplets is obtained, which can be exploited for drug delivery and encapsulation, nanoparticle synthesis, and template-free polymer array patterning.

Laser-Based Ultrasound Interrogation of Surface and Sub-Surface Features in Advanced Manufacturing Materials

2021 ◽  
Author(s):  
Kathryn Jinae Harke ◽  
Nicholas Calta ◽  
Joseph Tringe ◽  
David Stobbe
Keyword(s):  
Acoustic Waves ◽  
Surface Defects ◽  
Surface Acoustic Waves ◽  
Acoustic Energy ◽  
Advanced Manufacturing ◽  
Powder Bed ◽  
Surface Features ◽  
Performance Targets ◽  
All Optical ◽  
X Ray Computed

Abstract Structures formed by advanced manufacturing methods increasingly require nondestructive characterization to enable efficient fabrication and to ensure performance targets are met. This is especially important for aerospace, military, and high precision applications. Surface acoustic waves (SAW) generated by laser-based ultrasound can detect surface and sub-surface defects relevant for a broad range of AM processes, including laser powder bed fusion (LPBF). In particular, an all-optical SAW generation and detection configuration can effectively interrogate laser melt lines. Here we report on scattered acoustic energy from melt lines, voids, and surface features. Sub-surface voids are also characterized using X-ray Computed Tomography (CT). High resolution CT results are presented and compared with SAW measurements. Finite difference simulations inform experimental measurements and analysis.

scholarly journals Upregulated phospholipase D activity toward glycosylphosphatidylinositol-anchored proteins in micelle-like serum complexes in metabolically deranged rats and humans

2020 ◽  
Vol 318 (4) ◽  
pp. E462-E479 ◽  
Author(s):  
Günter A. Müller ◽  
Matthias H. Tschöp ◽  
Timo D. Müller
Keyword(s):  
Phospholipase D ◽  
Acoustic Waves ◽  
Surface Acoustic Waves ◽  
The Body ◽  
Full Length ◽  
Rat Serum ◽  
Metabolic Derangement ◽  
Insulin Resistant ◽  
Early States ◽  
Highly Sensitive

Glycosylphosphatidylinositol-anchored proteins (GPI-AP) with the complete glycolipid anchor attached have previously been shown to be released from the outer plasma membrane leaflet of rat adipocytes in positive correlation to cell size and blood glucose/insulin levels of the donor rats. Furthermore, they are present in rat and human serum, however, at amounts that are lower in insulin-resistant/obese rats compared with normal ones. These findings prompted further evaluation of the potential of full-length GPI-AP for the prediction and stratification of metabolically deranged states. A comparison of the signatures of horizontal surface acoustic waves that were generated by full-length GPI-AP in the course of their specific capture by and subsequent dissociation from a chip-based sensor between those from rat serum and those reconstituted into lipidic structures strongly argues for expression of full-length GPI-AP in serum in micelle-like complexes in concert with phospholipids, lysophospholipids, and cholesterol. Both the reconstituted and the rat serum complexes were highly sensitive toward mechanical forces, such as vibration. Furthermore, full-length GPI-AP reconstituted into micelle-like complexes represented efficient substrates for cleavage by serum glycosylphosphatidylinositol-specific phospholipase D (GPI-PLD). These findings raised the possibility that the upregulated release of full-length GPI-AP into micelle-like serum complexes from metabolically deranged cells is compensated by elevated GPI-PLD activity. In fact, serum GPI-PLD activity toward full-length GPI-AP in micelle-like complexes, but not in detergent micelles, was positively correlated to early states of insulin resistance and obesity in genetic and diet-induced rat models as well as to the body weight in humans. Moreover, the differences in the degradation of GPI-AP in micelle-like complexes were found to rely in part on the interaction of serum GPI-PLD with an activating serum factor. These data suggest that serum GPI-PLD activity measured with GPI-AP in micelle-like complexes is indicative of enhanced release of full-length GPI-AP from relevant tissues into the circulation as a consequence of early metabolic derangement in rats and humans.

Modeling Development of a High-Sensitivity Escherichia coli O157:H7 Detection Based on SH SAW Sensor

2014 ◽  
Vol 925 ◽  
pp. 595-599
Author(s):  
Seng Teik Ten ◽  
Uda Hashim ◽  
Ahmad Sudin ◽  
Wei Wen Liu ◽  
Kai Loong Foo ◽  
...  
Keyword(s):  
Acoustic Waves ◽  
High Performance ◽  
Surface Acoustic Waves ◽  
Equivalent Circuit Model ◽  
High Sensitivity ◽  
Theoretical Models ◽  
Acoustic Energy ◽  
Sensitive Detection ◽  
Label Free ◽  
Element Analysis

Surface acoustic waves based devices were initially developed for the telecommunication purpose such as signal filters and resonators. The acoustic energy is strongly confined on the surface of the surface acoustic waves (SAW) based devices and consequent their ultra-sensitivity to the surface perturbation. This has made SAW permits the highly sensitive detection of utterly diminutive charges on the surface. Hence, SAW based devices have been modified to be sensors. Food contamination has become critical issue and sensitive detection devices are needed urgently as small amount of harmful bacterial pathogens such as Escherichia coli (E.coli) O157:H7with the dose fewer than 100 organisms in food products or water is enough to cause serious gastrointestinal illness to human. Therefore, ultra-high sensitive, label free biosensors have been designed in this research for the low concentration E.coli detection. After the saturated development in telecommunication filed, SAW sensors were developed for gas detections and have been moving towards biological detections recently. Shear horizontal surface acoustic wave (SHSAW), one of the SAW based types is most suitable for the liquid based application as it has the advantage of acoustic energy is not being radiated into liquid. Therefore, SHSAW device has the potential to provide high-performance sensing platform in this research. There have been a lot of complicated theoretical models for the SAW devices development since 1960 as signal filters and resonators such as from delta function model, equivalent circuit model, to the current SAW models such as coupling-of-modes (COM) model, P-matrix model and finite element analysis (FEA) model. However, SHSAW device in this research is not meant for signal filter or resonators but used for surface sensing purpose, therefore the simplicity method of the modeling is presented in the paper for the E.coli detection sensor development.

Direct numerical calculation of acoustics: solution evaluation through energy analysis

1993 ◽  
Vol 254 ◽  
pp. 267-281 ◽  
Author(s):  
Kenneth S. Brentner
Keyword(s):  
Entropy Generation ◽  
Acoustic Waves ◽  
Fundamental Problem ◽  
Entropy Change ◽  
Inviscid Flow ◽  
The Body ◽  
Acoustic Energy ◽  
Cylinder Surface ◽  
Flow Solver ◽  
Temporal And Spatial Characteristics

The propagation of acoustic energy from a sound source to the far field is a fundamental problem of acoustics. In this paper the use of computational fluid dynamics (CFD) to directly calculate the acoustic field is investigated. The two-dimensional, compressible, inviscid flow about an accelerating circular cylinder is used as a model problem. The time evolution of the energy transfer from the cylinder surface to the fluid, as the cylinder is moved from rest to some non-negligible velocity, is shown. Energy is the quantity of interest in the calculations since various components of energy have physical meaning. By examining the temporal and spatial characteristics of the numerical solution, a distinction can be made between the propagating acoustic energy, the convecting energy associated with the entropy change in the fluid, and the energy following the body. In the calculations, entropy generation is due to a combination of physical mechanisms and numerical error. In the case of propagating acoustic waves, entropy generation seems to be a measure of numerical damping associated with the discrete flow solver.

scholarly journals Surface Acoustic Waves: A New Paradigm for Driving Ultrafast Biomicrofluidics

2009 ◽  
Author(s):  
Leslie Y. Yeo ◽  
James R. Friend
Keyword(s):  
Drug Delivery ◽  
Acoustic Waves ◽  
Sessile Drop ◽  
Surface Acoustic Waves ◽  
Capillary Waves ◽  
Liquid Jets ◽  
Powerful Method ◽  
New Paradigm ◽  
Nodal Lines ◽  
Planar Substrates

Surface acoustic waves (SAWs), which are 10 MHz order surface waves roughly 10 nm in amplitude propagating on the surface of a piezoelectric substrate, can offer a powerful method for driving fast microfluidic actuation and microparticle or biomolecule manipulation. We demonstrate that sessile drops can be linearly translated on planar substrates or fluid can be pumped through microchannels at typically one to two orders of magnitude faster than that achievable through current microfluidic technologies. Micromixing can be induced in the same microchannel in which fluid is pumped using the SAW simply by changing the SAW frequency to superimpose a chaotic oscillatory flow onto the uniform through flow. Strong inertial microcentrifugation for micromixing and particle concentration or separation can also be induced via symmetry-breaking. At low SAW amplitudes below that at which flow commences, the transverse standing wave that arises across the microchannel afford particle aggregation and hence sorting on nodal lines. Other microfluidic manipulations are also possible with the SAW. For example, capillary waves excited on a sessile drop by the SAW can be exploited for microparticle or nanoparticle collection and sorting. At higher amplitudes, the large substrate accelerations drives rapid destabilization of the drop interface giving rise to inertial liquid jets or atomization to produce 1–10 μm monodispersed aerosol droplets. These have significant implications for microfluidic chip mass spectrometry interfacing or pulmonary drug delivery. The atomization also provides a convenient means for the synthesis of 150–200 nm polymer or protein particles or to encapsulate proteins, peptides and other therapeutic molecules within biodegradable polymeric shells for controlled release drug delivery. The atomization of thin films containing polymer solutions, in addition, gives produces a unique regular, long-range spatial polymer spot patterning effect whose size and spacing are dependent on the SAW frequency, thus offering a simple and powerful method for surface patterning without requiring physical or chemical templating.

Design Development of Acoustic Waves Based Sensitive Sensors for Escherichia coli O157:H7 Detection

2014 ◽  
Vol 925 ◽  
pp. 590-594 ◽  
Author(s):  
Seng Teik Ten ◽  
Uda Hashim ◽  
Ahmad Sudin ◽  
Wei Wen Liu ◽  
Kai Loong Foo ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Acoustic Waves ◽  
Low Cost ◽  
Wave Length ◽  
Surface Acoustic Waves ◽  
High Volume ◽  
Acoustic Energy ◽  
Label Free ◽  
Design Development ◽  
Fecal Matter

Food contamination has become critical issue and is being worse due to the insensitive detection devices. One of the dangerous food contaminations is by Escherichia coli (E.coli) O157:H7, one of the harmful bacterial pathogens which is distributed in soil, marine and estuarine waters, the intestinal tract of animals, or water contaminated with fecal matter. A small amount of E.coli with the dose fewer than 100 organisms in food products or water is enough to cause serious gastrointestinal illness to human. Hence, the ultra-high sensitive, label free biosensors have been designed in this research for the low concentration E.coli detection. Surface acoustic waves (SAW) devices have been initially developed and used for the high-volume low-cost TV component. Due to the ultra-sensitivity to the surface perturbation, SAW based devices have been modified to be sensors. Initially, SAW sensors were developed for gas detections and have been moving towards biological detections recently. Shear horizontal surface acoustic wave (SHSAW), one of the SAW based types is most suitable for the liquid based application as it has the advantage of acoustic energy is not being radiated into liquid. However, the main SHSAW design components are the operating frequency and wave length. These are strictly depended on the inter digital transducers (IDTs) design. Therefore, this paper is presenting the IDTs design concept and pattern development by using computer aid design (CAD) software.

scholarly journals Frequency dependence of surface acoustic wave swimming

2019 ◽  
Vol 16 (155) ◽  
pp. 20190113
Author(s):  
C. Pouya ◽  
K. Hoggard ◽  
S. H. Gossage ◽  
H. R. Peter ◽  
T. Poole ◽  
...  
Keyword(s):  
Elastic Waves ◽  
Acoustic Waves ◽  
Body Shape ◽  
Surface Acoustic Waves ◽  
The Body ◽  
Evolutionary Significance ◽  
Test Bed ◽  
Optimum Frequency ◽  
Propulsion Mechanism ◽  
Beating Frequency

Surface acoustic waves (SAWs) are elastic waves that can be excited directly on the surface of piezoelectric crystals using a transducer, leading to their exploitation for numerous technological applications, including for example microfluidics. Recently, the concept of SAW streaming, which underpins SAW microfluidics, was extended to make the first experimental demonstration of ‘SAW swimming’, where instead of moving water droplets on the surface of a device, SAWs are used as a propulsion mechanism. Using theoretical analysis and experiments, we show that the SAW swimming force can be controlled directly by changing the SAW frequency, due to attenuation and changing force distributions within each SAW streaming jet. Additionally, an optimum frequency exists which generates a maximum SAW swimming force. The SAW frequency can therefore be used to control the efficiency and forward force of these SAW swimming devices. The SAW swimming propulsion mechanism also mimics that used by many microorganisms, where propulsion is produced by a cyclic distortion of the body shape. This improved understanding of SAW swimming provides a test-bed for exploring the science of microorganism swimming, and could bring new insight to the evolutionary significance for the length and beating frequency of swimming microbial flagella.

In-House Development of Shear Horizontal Acoustic Waves Based Sensitive Sensors for Bacterial Pathogens Detection

2015 ◽  
Vol 1109 ◽  
pp. 309-313
Author(s):  
Seng Teik Ten ◽  
Uda Hashim ◽  
Ahmad Sudin ◽  
Wei Wen Liu ◽  
Kai Loong Foo ◽  
...  
Keyword(s):  
Acoustic Wave ◽  
Surface Acoustic Wave ◽  
Acoustic Waves ◽  
Bacterial Pathogens ◽  
Substrate Surface ◽  
Ultra Violet ◽  
Elastic Solid ◽  
Acoustic Energy ◽  
Main Component ◽  
Shear Horizontal

Surface acoustic wave can be generated at the free surface of an elastic solid. Interdigital transducers (IDTs) are fabricated on the piezoelectric substrate surface that will act as electrical input and output port. When appropriate AC voltage stimulus is applied to the input transducer, surface acoustic wave will be produced. The output or receiving port will detect the incident surface acoustic wave and convert it back to a suitably filtered electrical once. For this property, surface acoustic based devices were initially developed for the telecommunication purpose such as signal filters and resonators. SAW based devices have been modified to be sensors later on from for gas detections and have been moving towards biological detections recently for its ultra-sensitivity to surface perturbation. The main component of this device is the IDTs. Recently, there are several methods to produce IDTs; Ultra-Violet (UV), deep UV lithography, Electron beam (e-beam) lithography and X-ray lithography. Although, these methods can produce very fine and accurate electrodes in term of submicron size but the costs are extremely expensive. Thus, this paper will discuss the conventional CMOS method which is much more economical to produce the applicable IDTs for the bacterial pathogens sensing purpose. Shear horizontal surface acoustic wave (SHSAW), one of the SAW based types is used in this paper as it is most suitable for the liquid based application as it has the advantage of acoustic energy is not being radiated into liquid.

Characterization of RF Sputtered ZnO Piezoelectric Films Using Transmission Electron Microscope

1975 ◽  
Vol 33 ◽  
pp. 86-87
Author(s):  
Kemining W. Yeh ◽  
Richard S. Muller ◽  
Wei-Kuo Wu ◽  
Jack Washburn
Keyword(s):  
Integrated Circuit ◽  
Acoustic Waves ◽  
New Technology ◽  
Surface Acoustic Waves ◽  
Electromechanical Properties ◽  
Leading Role ◽  
Saw Devices ◽  
Transmission Electron ◽  
High Degree

Considerable and continuing interest has been shown in the thin film transducer fabrication for surface acoustic waves (SAW) in the past few years. Due to the high degree of miniaturization, compatibility with silicon integrated circuit technology, simplicity and ease of design, this new technology has played an important role in the design of new devices for communications and signal processing. Among the commonly used piezoelectric thin films, ZnO generally yields superior electromechanical properties and is expected to play a leading role in the development of SAW devices.

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